Bent Spike-rush Southern Mountain population
Scientific Name: Eleocharis geniculata
Taxonomy Group: Vascular Plants
Range: British Columbia
Last COSEWIC Assessment: April 2009
Last COSEWIC Designation: Endangered
SARA Status: Schedule 1, Endangered
Image of Bent Spike-rush
Bent Spike–rush (Eleocharis geniculata) is a small, tufted annual sedge composed of numerous slender stalks (culms). Stalks are usually terminated by a single spikelet composed of bisexual flowers that produce black achenes (small dry fruitlets). Each achene is tipped with a flat and fairly wide tubercle. The black achenes separate this species from most other tufted Canadian species of Eleocharis. Until recently, collections of this species from Osoyoos Lake, British Columbia, had been identified as the Purple Spike–rush (E. atropurpurea), but research has shown this to be in error. (Updated 2017/05/25)
Distribution and Population
Bent Spike–rush is a pantropical species and is fairly widespread in the southern parts of North America. In Canada, ithas been reported from one location in British Columbia (on Osoyoos Indian Band property on the east shore of Osoyoos Lake) and from three sites in south–western Ontario along the northern shore of Lake Erie: Long Point National Wildlife Area, Cedar Springs, and at an historical site in Rondeau Provincial Park. Two designatable units (DU) are considered in this report: the Southern Mountain DU (British Columbia) and the Great Lakes Plains DU (Ontario). The total estimated area of habitat occupied in Canada is 1200 m2 in BC and 2000 m2 in Ontario. The Index of Area of Occupancy based on a 2x2 km grid is 16 km2 (4 km in BC and 12 km2 in ON). (Updated 2017/05/25)
In British Columbia, Bent Spike–rush has been found on soil at the edges of open ephemeral pond wetland complexes within the Bunchgrass Biogeoclimatic Zone. These ponds are flooded throughout much of the year, usually drying during the spring and summer, although sometimes they flood again in late summer. In Ontario, this species is found on wet, sandy to muddy soil in open flats on or along the edges of ephemeral ponds and wet meadows in the Deciduous Forest Region (Carolinian Zone). The Cedar Springs site appears to be an old sandpit. In British Columbia, the species’ habitat appears stable, but in Ontario the habitat is threatened by extensive invasions of the exotic strain of Common Reed (Phragmites australis). (Updated 2017/05/25)
Bent Spike–rush grows each year from overwintering achenes. Plants grow into early autumn and produce flowers and achenes, then wither and die during the onset of winter. Not all achenes that are produced germinate the following year. Some remain dormant, sometimes for many years, as a seedbank in the soil. Bent Spike–rush depends on a seedbank for its long–term persistence. Annual plants often have wide fluctuations in plant size and numbers, and the numbers of flowers and achenes produced from year to year. Dispersal is through movement of achenes as there is no means of asexual reproduction in this species. (Updated 2017/05/25)
The main natural limiting factor across the Canadian range of Bent Spike–rush is its restriction to a rather specific and geographically limited habitat. In British Columbia, trampling and soil disturbance by cattle and horses, human–related disturbances, invasive plants, especially grasses, and artificial management of the water levels of Lake Osoyoos are threats. The greatest threat to populations in Ontario is the rapid invasion of known and potential habitat by Common Reed. (Updated 2017/05/25)
Federal ProtectionThe Bent Spike-rush, Southern Mountain population, is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
Provincial and Territorial Protection
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
8 record(s) found.
- COSEWIC Status Reports (1 record(s) found.)
- COSEWIC Assessments (1 record(s) found.)
- Response Statements (1 record(s) found.)
- Orders (2 record(s) found.)
- COSEWIC Annual Reports (1 record(s) found.)
- Consultation Documents (1 record(s) found.)
- Recovery Document Posting Plans (1 record(s) found.)
COSEWIC Status Reports
COSEWIC Annual Reports
COSEWIC Annual Report - 2009 (2009)2009 Annual Report to the The Minister of the Environment and the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
Recovery Document Posting Plans
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